数据库的安装初始化及管理

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root@mysql \~\] # ls anaconda-ks.cfg initserver.sh mysql-8.0.33-1.el7.x86_64.rpm-bundle.tar mysql-community-client-8.0.33-1.el7.x86_64.rpm mysql-community-client-plugins-8.0.33-1.el7.x86_64.rpm mysql-community-common-8.0.33-1.el7.x86_64.rpm mysql-community-debuginfo-8.0.33-1.el7.x86_64.rpm mysql-community-devel-8.0.33-1.el7.x86_64.rpm mysql-community-embedded-compat-8.0.33-1.el7.x86_64.rpm mysql-community-icu-data-files-8.0.33-1.el7.x86_64.rpm mysql-community-libs-8.0.33-1.el7.x86_64.rpm mysql-community-libs-compat-8.0.33-1.el7.x86_64.rpm mysql-community-server-8.0.33-1.el7.x86_64.rpm mysql-community-server-debug-8.0.33-1.el7.x86_64.rpm mysql-community-test-8.0.33-1.el7.x86_64.rpm 2. 确定 mysql-community-server 正常安装之后就可以开始配置 3. 初始化 mysqld 服务 mysqld initeialize 4. 启动服务 systemctl start mysqld 5. 添加开机启动列表 systecmctrl enable mysqld 6. 在 /var/log/mysql.log 中找到初始密码，前后复制空格 7. 登录管理 mysql -uroot -p 将复制的密码粘贴到输入密码的区 域，实现登录 8. 设置新的密码 ![](https://i-blog.csdnimg.cn/direct/bf62a612c9c24ff1bd75b145b7b3bbd6.png) 9. 退出登录 ![](https://i-blog.csdnimg.cn/direct/e586ad169741447b863ab2b48c8c91b9.png) **1.** **数据库的对象** 1. 数据库系统 DBMS 2. 数据库 DB 3. 表 table 4. 记录 record 5. 字段 feild **1.** **数据库操作** **删除库** ![](https://i-blog.csdnimg.cn/direct/d4a6037514e74640b5ccdc09780a2013.png) **创建库** mysql \> create datababse test charset utf8; Query OK, 1 row affected, 1 warning ( 0.01 sec ) mysql \> show databases ; **查看库** **2.** **表的操作** **1.** **选择库** +--------------------+ ![](https://i-blog.csdnimg.cn/direct/3c074c925e86428985ba4afbac88e6a4.png) mysql \> create datababse test charset utf8; Query OK, 1 row affected, 1 warning ( 0.01 sec ) mysql \> show databases ; **查看库** **2.** **表的操作** **1.** **选择库** ![](https://i-blog.csdnimg.cn/direct/9e8e31a0f7724f2e821227c53a3407df.png) ![](https://i-blog.csdnimg.cn/direct/2b632cef7c854cd3886bc4c9111f895e.png) **2.** **查看表** ![](https://i-blog.csdnimg.cn/direct/d8c69ab9e33d4f21af02c230476d65fa.png) ![](https://i-blog.csdnimg.cn/direct/1805972d59cc4df3b84075dd6602d174.png) **3.** **创建表** ![](https://i-blog.csdnimg.cn/direct/8abb5cbec0774cb7bfa3e80154944947.png) mysql \> CREATE TABLE \`test\` . \`user\` ( -\> \`id\` INT NOT NULL AUTO_INCREMENT , -\> \`username\` VARCHAR ( 45 ) NOT NULL , -\> \`password\` VARCHAR ( 45 ) NOT NULL , -\> PRIMARY KEY ( \`id\` ) , -\> UNIQUE INDEX \`username_UNIQUE\` ( \`username\` ASC ) VISIBLE ) -\> COMMENT = 'us' ; mysql \> show tables ; +----------------+ \| Tables_in_test \| +----------------+ \| user \| \| user0 \| **4.** **删除表** **新增列** mysql \> show tables ; +----------------+ \| Tables_in_test \| +----------------+ \| user \| \| user0 \| +----------------+ 2 rows in set ( 0.00 sec ) mysql \> drop table user0; Query OK, 0 rows affected ( 0.01 sec ) mysql \> show tables ; +----------------+ \| Tables_in_test \| +----------------+ \| user \| +----------------+ 1 row in set ( 0.01 sec ) ALTER TABLE \`test\`.\`user\` ADD COLUMN \`realname\` VARCHAR(45) NULL AFTER \`password\`; mysql\> desc user; +----------+-------------+------+-----+---------+--------- -------+ \| Field \| Type \| Null \| Key \| Default \| Extra \| +----------+-------------+------+-----+---------+--------- -------+ \| id \| int \| NO \| PRI \| NULL \| auto_increment \| \| username \| varchar(45) \| NO \| UNI \| NULL \| \| **修改列名** \| password \| varchar(45) \| NO \| \| NULL \| \| \| realname \| varchar(45) \| YES \| \| NULL \| \| +----------+-------------+------+-----+---------+--------- -------+ 4 rows in set (0.01 sec) mysql\> ALTER TABLE \`test\`.\`user\` -\> CHANGE COLUMN \`realname\` \`zsxm\` VARCHAR(45) NULL DEFAULT NULL ; Query OK, 0 rows affected (0.02 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql\> desc user; +----------+-------------+------+-----+---------+--------- -------+ \| Field \| Type \| Null \| Key \| Default \| Extra \| +----------+-------------+------+-----+---------+--------- -------+ \| id \| int \| NO \| PRI \| NULL \| auto_increment \| \| username \| varchar(45) \| NO \| UNI \| NULL \| \| \| password \| varchar(45) \| NO \| \| NULL \| \| \| zsxm \| varchar(45) \| YES \| \| NULL \| \| +----------+-------------+------+-----+---------+--------- -------+ **删除列** 5. 其他 3. 记录的操作 1. 新增 mysql \> ALTER TABLE \`test\` . \`user\` -\> DROP COLUMN \`zsxm\` ; Query OK, 0 rows affected ( 0.01 sec ) Records: 0 Duplicates: 0 Warnings : 0 mysql \> desc user ; +----------+-------------+------+-----+---------+--------- -------+ \| Field \| Type \| Null \| Key \| Default \| Extra \| +----------+-------------+------+-----+---------+--------- -------+ \| id \| int \| NO \| PRI \| NULL \| auto_increment \| \| username \| varchar ( 45 ) \| NO \| UNI \| NULL \| \| \| password \| varchar ( 45 ) \| NO \| \| NULL \| \| +----------+-------------+------+-----+---------+--------- -------+ 3 rows in set ( 0.00 sec ) #insert into 表名 ( 字段名列表 ) values ( 字段值列表 ) mysql \> select \* from user ; Empty set ( 0.00 sec ) mysql \> insert into user ( id,username, password ) values ( 3 , 'zhangsan' , 'zhangsan' ) ; Query OK, 1 row affected ( 0.01 sec ) mysql \> select \* from user ; +----+----------+----------+ \| id \| username \| password \| +----+----------+----------+ \| 3 \| zhangsan \| zhangsan \| +----+----------+----------+ 1 row in set ( 0.00 sec ) mysql \> select \* from user ; +----+----------+----------+ \| id \| username \| password \| +----+----------+----------+ \| 3 \| zhangsan \| zhangsan \| +----+----------+----------+ 1 row in set ( 0.00 sec ) mysql \> insert into user ( username, password ) values ( 'lisi' , 'lisi' ) ; Query OK, 1 row affected ( 0.00 sec ) mysql \> select \* from user ; +----+----------+----------+ \| id \| username \| password \| +----+----------+----------+ \| 3 \| zhangsan \| zhangsan \| \| 4 \| lisi \| lisi \| +----+----------+----------+ 2 rows in set ( 0.00 sec ) mysql \> desc user ; +----------+-------------+------+-----+---------+------ ----------+ \| Field \| Type \| Null \| Key \| Default \| Extra \| +----------+-------------+------+-----+---------+------ ----------+ \| id \| int \| NO \| PRI \| NULL \| auto_increment \| \| username \| varchar ( 45 ) \| NO \| UNI \| NULL \| \| \| password \| varchar ( 45 ) \| NO \| \| NULL \| \| +----------+-------------+------+-----+---------+------ ----------+ 3 rows in set ( 0.00 sec ) 2. 删除 delte from user where 条件 ; mysql \> delete from user where username = 'zhangsan' ; Query OK, 1 row affected ( 0.00 sec ) mysql \> select \* from user ; +----+----------+----------+ \| id \| username \| password \| +----+----------+----------+ \| 4 \| lisi \| lisi \| +----+----------+----------+ 1 row in set ( 0.00 sec ) mysql \> delete from user ; Query OK, 1 row affected ( 0.00 sec ) mysql \> select \* from user ; Empty set ( 0.00 sec ) 3. 修改 mysql \> mysql \> insert into user values ( 1 , 'zhangsan' , 'zhangsan' ) ; Query OK, 1 row affected ( 0.00 sec ) mysql \> insert into user values ( 2 , 'lisi' , 'lisi' ) ; Query OK, 1 row affected ( 0.00 sec ) mysql \> insert into user values ( 3 , 'wangwu' , 'wangwu' ) ; Query OK, 1 row affected ( 0.00 sec ) mysql \> select \* from user ; +----+----------+----------+ \| id \| username \| password \| +----+----------+----------+ \| 1 \| zhangsan \| zhangsan \| \| 2 \| lisi \| lisi \| \| 3 \| wangwu \| wangwu \| +----+----------+----------+ 3 rows in set ( 0.00 sec ) mysql \> update user set password = 123 where username = 'zhangsan' ; Query OK, 1 row affected ( 0.01 sec ) Rows matched: 1 Changed : 1 Warnings : 0 mysql \> select \* from user ; +----+----------+----------+ \| id \| username \| password \| +----+----------+----------+ \| 1 \| zhangsan \| 123 \| \| 2 \| lisi \| lisi \| \| 3 \| wangwu \| wangwu \| +----+----------+----------+ 3 rows in set ( 0.00 sec ) 4. 查询